I've drilled a small hole in the plastic V2 sprockets prior to installing. The hole is in the exact center of the sprocket, right on the sprocket ridge exactly 180degrees opposite the master tooth. The sprockets have a mold mark that marks the perfect place.
The small hole goes through the sprocket to reach where the sprocket shaft would reside. The hole is quite small about 1/16" or 3/64". the hole diameter is determined by the size of the grease needle you purchase.
The grease needle needs to fit very tightly into the hole, but still be able to be inserted. Clean off any chaff and reinstall your plastic sprockets. You can now grease them any time in only minutes. If done correctly the pressure from the grease needle will force grease into the sprocket so that it comes out both ends, forcing out old grease/dirt and leaving sprocket & shaft properly lubricated.
Several caveats for project. Sprocket must be removed from drive to drill hole.
Hole must be perfect size to match grease needle - too loose a hole will allow grease to be forced past the grease needle rather than forced into shaft/sprocket cavity. You might want to practice drill a PVC fitting and check with grease needle.
Finally, don't stick yourself with the needle
The hole placement distributes grease evenly and, with the flippers fully spread, allows you to reach holes easily with gun & needle
I use marine grease.
a grease needle source - snaps on grease gunshttp://www.tractorsupply.com/webapp/wcs/stores/servlet/ProductDisplay_10551_10001_172708_-1______?rFlag=true&cFlag=1
The above grease needle is 18 gauge which is .05" diameter which means a 3/64" dremel drill (.0468) should be used.
If you find a 16 gauge grease needle = .0650" in diameter you then can drill using an easier to find 1/16" drill (.0625).
Notice in all cases the drill is fractionally smaller than the needle size.
If you are worried about plugging the hole after greasing the sprockets a round toothpick cut short works just fine.
Yakaholicedited to fix link